Advice on best frame size for me



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D

Death

Guest
Hello,

I am in the process of putting together a new bike and I am having trouble making a decision of
which of two frame sizes I should choose. I know that the right answer is to ride both sizes and
pick the one that fits best, unfortunately I do not have this option. There is no dealer near me
that carries the brand I am interested in(Soma) and even if there were it would have to be an
exceptional shop that would stock several different sizes of fixed gear/track frames. I have lived
in cities where exceptional shops existed, I miss them.

I recently paid a local Serotta dealer to fit me using their Size Cycle. According to the data sheet
generated by this fitting I will be the most comfortable on a frame with a 57 cm seat tube
length(measured center to center) and a 56.5 cm top tube using a 11 cm stem.

I am having difficulty deciding between a 57 or a 59 frame. Soma measures their frames center to the
top of the seat tube, so I am guessing that their 57 measures 56 c to c and their 59 measures 58 c
to c. The top tube for the 57 is 56 cm and the top tube for the 59 is 57.5 cm. The standover on the
57 is 32.5" the 59 is 33.3" my inseam is 33.6". I suppose my question boils down to this: would I be
better off with more seat post extension and a longer stem(12 or 13) or less seat post extension and
a shorter stem(9 or
10)? And should I worry about only having .3" between the top tube and my crotch while standing if I
choose the 59?

The Size Cycle measurements were made to determine an ideal road bike frame, so the bottom
bracket of my target geometry has a 26 cm height, the Soma track frame has a 27.5 cm bb height.
Also, the head & seat tube angles are about 1.5 deg sharper on the track bike than the imaginary
ideal road bike.

You say you want more information? No problem: I am 6'1, 33.6" inseam. The bike I currently have for
road/light off road use(the first non mountain or BMX bike I have owned) is a Kona cyclocross bike,
58 cm center to top of seat tube, 57 cm top tube and a 10 cm stem. It shows about 6.5" of post to
the bottom of the seat. It has a 31.2 cm bb height & 33.1" standover. I think it fits pretty well,
but could be better.

I plan to use the new bike with a fixed gear and ride almost exclusively on 20-30 mile trips over
mostly flat road. I realize an off the shelf frame will never match what is calculated from a custom
fitting, and perhaps given the intended application of this bike(mostly short, training oriented
rides) maybe perfect comfort fitting is not all that important. But I have made some bad equipment
decisions in the past because I did not do enough research or ask the right questions, and I would
really like to have peace of mind with this decision so that I can concentrate on using the bike. I
know that there are some folks here who have much more experience with frame sizing than myself and
if any of you have made it this far, to the end of my autobiography, I would greatly appreciate any
input or suggestions you may have.
 
T

Tim McNamara

Guest
Go with the bigger frame. You don't say how old you are but as you get older, the ability to have
the bars a little higher will come in handy. Trust me on this... ;-)
 
K

Ken

Guest
"death" <[email protected]*.no*spam> wrote in news:[email protected]:
> I am having difficulty deciding between a 57 or a 59 frame. Soma measures their frames center to
> the top of the seat tube, so I am guessing that their 57 measures 56 c to c and their 59
> measures 58 c to
> c. The top tube for the 57 is 56 cm and the top tube for the 59 is 57.5
> cm. The standover on the 57 is 32.5" the 59 is 33.3" my inseam is 33.6".

Is the size to the top of the seat tube or to the top of the top tube? On some kinds of frames
(especially carbon fiber), the seat tube extends 1 or 2 cm above the top tube. On a frame like that,
there can be a 3 or 4 cm difference between the nominal frame size and the c-c measurement.

For larger frame sizes, I think seat tube isn't a very good fit metric anyway. Taller riders
generally choose frames with pleanty of standover clearance. The more important metric is your top
tube length. Head tube length is also important, since a too tall headtube affects how low you can
position the handlebars.
 
K

Kbh

Guest
I would recommend erring on the side of a larger frame. As a previous poster mentioned, bar height
is a key consideration, and with modern aheadsets, its best to get the frame up high to begin
with, rather than rely on a stack of spacers if you end up needing them. I subscribe to
Rivendell's sizing methodology (http://www.rivbike.com/html/bikes_framesize.html) , one part of
which is that you really don't need much standover, i.e. its OK if your package makes contact with
the TT while standing.

"death" <[email protected]*.no*spam> wrote in message
news:[email protected]...
> Hello,
>
> I am in the process of putting together a new bike and I am having trouble making a decision of
> which of two frame sizes I should choose. I know that the right answer is to ride both sizes and
> pick the one that fits best, unfortunately I do not have this option. There is no dealer near me
> that carries the brand I am interested in(Soma) and even if there were it would have to be an
> exceptional shop that would stock several different sizes of fixed gear/track frames. I have lived
> in cities where exceptional shops existed, I miss them.
>
> I recently paid a local Serotta dealer to fit me using their Size Cycle. According to the data
> sheet generated by this fitting I will be the most comfortable on a frame with a 57 cm seat tube
> length(measured center to center) and a 56.5 cm top tube using a 11 cm stem.
>
> I am having difficulty deciding between a 57 or a 59 frame. Soma measures their frames center to
> the top of the seat tube, so I am guessing that
their
> 57 measures 56 c to c and their 59 measures 58 c to c. The top tube for
the
> 57 is 56 cm and the top tube for the 59 is 57.5 cm. The standover on the
57
> is 32.5" the 59 is 33.3" my inseam is 33.6". I suppose my question boils down to this: would I be
> better off with more seat post extension and a longer stem(12 or 13) or less seat post extension
> and a shorter stem(9 or
> 10)? And should I worry about only having .3" between the top tube and my crotch while standing if
> I choose the 59?
>
> The Size Cycle measurements were made to determine an ideal road bike
frame,
> so the bottom bracket of my target geometry has a 26 cm height, the Soma track frame has a 27.5 cm
> bb height. Also, the head & seat tube angles are about 1.5 deg sharper on the track bike than the
> imaginary ideal road
bike.
>
> You say you want more information? No problem: I am 6'1, 33.6" inseam. The bike I currently have
> for road/light off road use(the first non mountain
or
> BMX bike I have owned) is a Kona cyclocross bike, 58 cm center to top of seat tube, 57 cm top tube
> and a 10 cm stem. It shows about 6.5" of post to the bottom of the seat. It has a 31.2 cm bb
> height & 33.1" standover. I think it fits pretty well, but could be better.
>
> I plan to use the new bike with a fixed gear and ride almost exclusively
on
> 20-30 mile trips over mostly flat road. I realize an off the shelf frame will never match what is
> calculated from a custom fitting, and perhaps
given
> the intended application of this bike(mostly short, training oriented
rides)
> maybe perfect comfort fitting is not all that important. But I have made some bad equipment
> decisions in the past because I did not do enough research or ask the right questions, and I would
> really like to have peace of mind with this decision so that I can concentrate on using the bike.
> I know that there are some folks here who have much more experience with
frame
> sizing than myself and if any of you have made it this far, to the end of
my
> autobiography, I would greatly appreciate any input or suggestions you may have.
 
D

Death

Guest
Thanks for the response. The measurements are to the top of the seat tube. I agree that the top tube
length is more important to me, but I'm unsure if it is better to compensate with a short stem or a
long stem.

I am not sure what he head tube length is on these frames, the manufacturer does not have that in
their specs.

"Ken" <[email protected]> wrote in message news:[email protected]...
> "death" <[email protected]*.no*spam> wrote in news:[email protected]:
> > I am having difficulty deciding between a 57 or a 59 frame. Soma measures their frames center to
> > the top of the seat tube, so I am guessing that their 57 measures 56 c to c and their 59
> > measures 58 c to
> > c. The top tube for the 57 is 56 cm and the top tube for the 59 is 57.5
> > cm. The standover on the 57 is 32.5" the 59 is 33.3" my inseam is 33.6".
>
> Is the size to the top of the seat tube or to the top of the top tube? On some kinds of frames
> (especially carbon fiber), the seat tube extends 1 or
2
> cm above the top tube. On a frame like that, there can be a 3 or 4 cm difference between the
> nominal frame size and the c-c measurement.
>
> For larger frame sizes, I think seat tube isn't a very good fit metric anyway. Taller riders
> generally choose frames with pleanty of standover clearance. The more important metric is your top
> tube length. Head tube length is also important, since a too tall headtube affects how low you
can
> position the handlebars.
 
D

Death

Guest
Thanks for the response. I'm 36. It was determined during my fitting that I will be better off using
a lot(3cm) of stem spacers and 10 degree rise stem. It seems to me that with a steeper head tube
angle that maybe the rise won't be as important(but I really don't know). One of my training goals
is to get more flexible and hopefully be more comfortable with lower bars, but I'm not really buying
the frame with this in mind. Your point definitely makes sense. I am just not sure how comfortable I
am going to be with about .5" of standover.

"Tim McNamara" <[email protected]> wrote in message news:[email protected]...
> Go with the bigger frame. You don't say how old you are but as you get older, the ability to have
> the bars a little higher will come in handy. Trust me on this... ;-)
 
D

Death

Guest
Thank you for pointing me to that info, I found that to be very helpful.

"KBH" <[email protected]> wrote in message news:p[email protected]_s03...
> I would recommend erring on the side of a larger frame. As a previous poster mentioned, bar height
> is a key consideration, and with modern aheadsets, its best to get the frame up high to begin
> with, rather than
rely
> on a stack of spacers if you end up needing them. I subscribe to Rivendell's sizing methodology
> (http://www.rivbike.com/html/bikes_framesize.html) , one part of which is that you really don't
> need much standover, i.e. its OK if your package
makes
> contact with the TT while standing.
>
>
> "death" <[email protected]*.no*spam> wrote in message
> news:[email protected]...
> > Hello,
> >
> > I am in the process of putting together a new bike and I am having
trouble
> > making a decision of which of two frame sizes I should choose. I know
that
> > the right answer is to ride both sizes and pick the one that fits best, unfortunately I do not
> > have this option. There is no dealer near me that carries the brand I am interested in(Soma) and
> > even if there were it
would
> > have to be an exceptional shop that would stock several different sizes
of
> > fixed gear/track frames. I have lived in cities where exceptional shops existed, I miss them.
> >
> > I recently paid a local Serotta dealer to fit me using their Size Cycle. According to the data
> > sheet generated by this fitting I will be the most comfortable on a frame with a 57 cm seat tube
> > length(measured center to center) and a 56.5 cm top tube using a 11 cm stem.
> >
> > I am having difficulty deciding between a 57 or a 59 frame. Soma
measures
> > their frames center to the top of the seat tube, so I am guessing that
> their
> > 57 measures 56 c to c and their 59 measures 58 c to c. The top tube for
> the
> > 57 is 56 cm and the top tube for the 59 is 57.5 cm. The standover on the
> 57
> > is 32.5" the 59 is 33.3" my inseam is 33.6". I suppose my question boils down to this: would I
> > be better off with more seat post extension and a longer stem(12 or 13) or less seat post
> > extension and a shorter stem(9
or
> > 10)? And should I worry about only having .3" between the top tube and
my
> > crotch while standing if I choose the 59?
> >
> > The Size Cycle measurements were made to determine an ideal road bike
> frame,
> > so the bottom bracket of my target geometry has a 26 cm height, the Soma track frame has a 27.5
> > cm bb height. Also, the head & seat tube angles
are
> > about 1.5 deg sharper on the track bike than the imaginary ideal road
> bike.
> >
> > You say you want more information? No problem: I am 6'1, 33.6" inseam.
The
> > bike I currently have for road/light off road use(the first non mountain
> or
> > BMX bike I have owned) is a Kona cyclocross bike, 58 cm center to top of seat tube, 57 cm top
> > tube and a 10 cm stem. It shows about 6.5" of post
to
> > the bottom of the seat. It has a 31.2 cm bb height & 33.1" standover. I think it fits pretty
> > well, but could be better.
> >
> > I plan to use the new bike with a fixed gear and ride almost exclusively
> on
> > 20-30 mile trips over mostly flat road. I realize an off the shelf frame will never match what
> > is calculated from a custom fitting, and perhaps
> given
> > the intended application of this bike(mostly short, training oriented
> rides)
> > maybe perfect comfort fitting is not all that important. But I have made some bad equipment
> > decisions in the past because I did not do enough research or ask the right questions, and I
> > would really like to have
peace
> > of mind with this decision so that I can concentrate on using the bike.
I
> > know that there are some folks here who have much more experience with
> frame
> > sizing than myself and if any of you have made it this far, to the end
of
> my
> > autobiography, I would greatly appreciate any input or suggestions you
may
> > have.
> >
>
 
T

Tim McNamara

Guest
"death" <[email protected]*.no*spam> writes:

> Thanks for the response. I'm 36. It was determined during my fitting that I will be better off
> using a lot(3cm) of stem spacers and 10 degree rise stem.

Sounds like you need the higher bars. But I'm a little baffled by this clearance issue. You say
you're 6'1"? I'm 6'4" and about a 63 cm frame (center to top) fits me pretty well. Seems to me like
you should be able to ride a 60 cm frame without any problem, unless it's got a *really* high
bottom bracket.

It's better to compensate for a slightly too-long top tube with a shorter stem than vice versa. Long
stems start to have deleterious effects on handling, IMHO. It's the "tiller" effect.
 
M

Matt O'Toole

Guest
"Ken" <[email protected]> wrote in message news:[email protected]...

> Head tube length is also important, since a too tall headtube affects how low you can position the
> handlebars.

Yes it does, but in the larger sizes most people have the opposite problem -- getting the bars
high enough.

Matt O.
 
D

Death

Guest
You say you're 6'1"? I'm 6'4" and about a 63
> cm frame (center to top) fits me pretty well. Seems to me like you should be able to ride a 60 cm
> frame without any problem, unless it's got a *really* high bottom bracket.

Well, I entered this process thinking a 59 or 60 would be what I needed, simply based on my height.
I have spent a fair amount of time on a 60 Colnago Master X which felt great. I was baffled when the
Size Cycle tech told me I should shop for a 57(for a few days I was convinced that my legs were
freakishly short vs my torso), but he was thinking bb center to top tube center. After doing a lot
of research I have the impression that most frames are not measured c-c(at least not by the brands I
considered for this bike). So, after much deliberation, I'm back to thinking I want a 59 cm
frame(measured center to seat tube top) for this bike, which, because it has "track" geometry, will
have a tallish bb. However, I am leaving this exercise with the opinion that there is little
consistency among frame builders(and I did not even consider a frame with compact geometry). If you
care about how your bike fits you need to do your homework. Perhaps when I get to the point when I
am ready to assemble a traditional geared road bike I will have saved enough money to get a frame
built to my measurements. Or maybe I should just learn how to weld.
 
M

Matt O'Toole

Guest
"Tim McNamara" <[email protected]> wrote in message news:[email protected]...

> "death" <[email protected]*.no*spam> writes:
>
> > Thanks for the response. I'm 36. It was determined during my fitting that I will be better off
> > using a lot(3cm) of stem spacers and 10 degree rise stem.
>
> Sounds like you need the higher bars. But I'm a little baffled by this clearance issue. You say
> you're 6'1"? I'm 6'4" and about a 63 cm frame (center to top) fits me pretty well. Seems to me
> like you should be able to ride a 60 cm frame without any problem, unless it's got a *really* high
> bottom bracket.
>
> It's better to compensate for a slightly too-long top tube with a shorter stem than vice versa.
> Long stems start to have deleterious effects on handling, IMHO. It's the "tiller" effect.

I agree with that. FWIW, I'm 6'0", and I usually ride a 60cm frame with a 58cm top tube. I don't
like a top tube any shorter than that. Another thing to consider is the head tube length. Most
modern bikes are too low in front to begin with. Bigger frames have longer head tubes, and the bars
up higher. You're already talking about long steerers and plenty of spacers. So start with a high
front end to begin with.

Matt O.
 
M

Mike Jacoubowsk

Guest
How much drop do you like from seat to bars? I'd use that as the deciding factor between the two
frame sizes. If you have to go to a 9.5cm stem with the taller frame, everything will still work
just fine.

The standover height isn't really an issue on a road bike, except that it's an indication of
nominal bar height vs seat height (less standover height implies the bars will be closer in height
to the saddle).

--Mike-- Chain Reaction Bicycles http://www.ChainReactionBicycles.com

"death" <[email protected]*.no*spam> wrote in message
news:[email protected]...
> Hello,
>
> I am in the process of putting together a new bike and I am having trouble making a decision of
> which of two frame sizes I should choose. I know that the right answer is to ride both sizes and
> pick the one that fits best, unfortunately I do not have this option. There is no dealer near me
> that carries the brand I am interested in(Soma) and even if there were it would have to be an
> exceptional shop that would stock several different sizes of fixed gear/track frames. I have lived
> in cities where exceptional shops existed, I miss them.
>
> I recently paid a local Serotta dealer to fit me using their Size Cycle. According to the data
> sheet generated by this fitting I will be the most comfortable on a frame with a 57 cm seat tube
> length(measured center to center) and a 56.5 cm top tube using a 11 cm stem.
>
> I am having difficulty deciding between a 57 or a 59 frame. Soma measures their frames center to
> the top of the seat tube, so I am guessing that
their
> 57 measures 56 c to c and their 59 measures 58 c to c. The top tube for
the
> 57 is 56 cm and the top tube for the 59 is 57.5 cm. The standover on the
57
> is 32.5" the 59 is 33.3" my inseam is 33.6". I suppose my question boils down to this: would I be
> better off with more seat post extension and a longer stem(12 or 13) or less seat post extension
> and a shorter stem(9 or
> 10)? And should I worry about only having .3" between the top tube and my crotch while standing if
> I choose the 59?
>
> The Size Cycle measurements were made to determine an ideal road bike
frame,
> so the bottom bracket of my target geometry has a 26 cm height, the Soma track frame has a 27.5 cm
> bb height. Also, the head & seat tube angles are about 1.5 deg sharper on the track bike than the
> imaginary ideal road
bike.
>
> You say you want more information? No problem: I am 6'1, 33.6" inseam. The bike I currently have
> for road/light off road use(the first non mountain
or
> BMX bike I have owned) is a Kona cyclocross bike, 58 cm center to top of seat tube, 57 cm top tube
> and a 10 cm stem. It shows about 6.5" of post to the bottom of the seat. It has a 31.2 cm bb
> height & 33.1" standover. I think it fits pretty well, but could be better.
>
> I plan to use the new bike with a fixed gear and ride almost exclusively
on
> 20-30 mile trips over mostly flat road. I realize an off the shelf frame will never match what is
> calculated from a custom fitting, and perhaps
given
> the intended application of this bike(mostly short, training oriented
rides)
> maybe perfect comfort fitting is not all that important. But I have made some bad equipment
> decisions in the past because I did not do enough research or ask the right questions, and I would
> really like to have peace of mind with this decision so that I can concentrate on using the bike.
> I know that there are some folks here who have much more experience with
frame
> sizing than myself and if any of you have made it this far, to the end of
my
> autobiography, I would greatly appreciate any input or suggestions you may have.
 
A

Arthur Harris

Guest
"death" wrote:

> I recently paid a local Serotta dealer to fit me using their Size Cycle. According to the data
> sheet generated by this fitting I will be the most comfortable on a frame with a 57 cm seat tube
> length(measured center to center) and a 56.5 cm top tube using a 11 cm stem.

> I am having difficulty deciding between a 57 or a 59 frame. Soma measures their frames center to
> the top of the seat tube, so I am guessing that
their
> 57 measures 56 c to c and their 59 measures 58 c to c.

If they measure from center of BB to top of seat tube:

Their 57cm will be more like a 55cm c-c. Their 59cm will be more like a 57cm c-c.

> The standover on the 57 is 32.5" the 59 is 33.3" my inseam is 33.6".

I assume the 33.6 inseam is barefoot. When wearing your normal cycling shoes, you'll have more
clearance than you think.

> The Size Cycle measurements were made to determine an ideal road bike
frame,
> so the bottom bracket of my target geometry has a 26 cm height, the Soma track frame has a 27.5 cm
> bb height. Also, the head & seat tube angles are about 1.5 deg sharper on the track bike than the
> imaginary ideal road
bike.

Wow! Those are big differences. I'd be very concerned about the steep seat tube angle. What is the
actual angle? That will certainly affect your saddle position. You will have to move your saddle
further back which will make your effective top tube length greater. Based on that alone, the
smaller frame would appear to be the better choice. But I think I'd keep looking for another brand
that's more attuned to your ideal measurements.

Art Harris
 
Q

Qui Si Parla Ca

Guest
death-<< I recently paid a local Serotta dealer to fit me using their Size Cycle. According to the
data sheet generated by this fitting I will be the most comfortable on a frame with a 57 cm seat
tube length(measured center to center) and a 56.5 cm top tube using a 11 cm stem.

I am having difficulty deciding between a 57 or a 59 frame. Soma measures their frames center to the
top of the seat tube, so I am guessing that their 57 measures 56 c to c and their 59 measures 58 c
to c. The top tube for the 57 is 56 cm and the top tube for the 59 is 57.5 cm. The standover on the
57 is 32.5" the 59 is 33.3" my inseam is 33.6". I suppose my question boils down to this: would I be
better off with more seat post extension and a longer stem(12 or 13) or less seat post extension and
a shorter stem(9 or
10)? And should I worry about only having .3" between the top tube and my crotch while standing if
>><BR><BR>

Are the seat tube ANGLES the same??

What angle did the Serotta session recommend? Remember if done right, that 'ideal' will move your
saddle fore/aft for the Soma, unless it matches, affecting your top tube length and stem.

Peter Chisholm Vecchio's Bicicletteria 1833 Pearl St. Boulder, CO, 80302
(11)440-3535 http://www.vecchios.com "Ruote convenzionali costruite eccezionalmente bene"
 
R

Robin Hubert

Guest
"death" <[email protected]*.no*spam> wrote in message
news:[email protected]...
>
> Thanks for the response. I'm 36. It was determined during my fitting that
I
> will be better off using a lot(3cm) of stem spacers and 10 degree rise stem. It seems to me
> that with a
steeper
> head tube angle that maybe the rise won't be as important(but I really
don't
> know). One of my training goals is to get more flexible and hopefully be more comfortable with
> lower bars, but I'm not really buying the frame with this in mind. Your point definitely makes
> sense. I am just not sure how comfortable I am going to be with about .5" of standover.

Standover is over-rated. I would go so far as to say it's a non--issue.

As for getting the bars low, you can always do that with the bigger bike. Follow Tim's advice and go
for the largest frame you can ride with a reasonable stem (8cm). You don't want shorter 'cause later
on down the road you might want to shorten it up a bit, and you need room to shrink, so to speak.

> "Tim McNamara" <[email protected]> wrote in message news:[email protected]...
> > Go with the bigger frame. You don't say how old you are but as you get older, the ability to
> > have the bars a little higher will come in handy. Trust me on this... ;-)
>

Robin Hubert
 
A

Arthur Harris

Guest
"Tim McNamara" wrote:

> Sounds like you need the higher bars. But I'm a little baffled by this clearance issue. You say
> you're 6'1"? I'm 6'4" and about a 63 cm frame (center to top) fits me pretty well. Seems to me
> like you should be able to ride a 60 cm frame without any problem, unless it's got a *really* high
> bottom bracket.

I like big frames myself for the same reason (higher bars). I'm 6'3" and have two bikes: 63cm c-c,
and 62cm c-c. Inseam is is 35.5" and I have no problem with standover clearance when wearing
cycling shoes.

But "Death" has a 33.6" inseam, a high (27.5 cm) BB height, and very steep seat tube. That's part of
the problem.

> It's better to compensate for a slightly too-long top tube with a shorter stem than vice versa.
> Long stems start to have deleterious effects on handling, IMHO. It's the "tiller" effect.

Except that in this case the frame has a 1.5 degree steeper seat angle than the "Fit Kit" that was
used to determine his ideal TT length. That means he has to slide the saddle back, increasing the
effective top tube length. And the "actual" TT is 1cm longer than his ideal to begin with.

Yeah, I'm sure he could get it to work, but I think I'd keep looking for a more suitable frame.

Art Harris
 
D

Death

Guest
Thanks for the response.

> Are the seat tube ANGLES the same??

>
> What angle did the Serotta session recommend? Remember if done right, that 'ideal' will move your
> saddle fore/aft for the Soma, unless it matches, affecting your top tube length and stem.

The seat tube angle of the "ideal" frame is 73.5 degrees. The Soma frames have a 75.3 degree seat
tube angle on the 57, and a 75.0 on the 59. I'm confused, does the sharper angle of the Soma
lengthen the distance of the tt/stem measurement? How can you determine how much(in cm) the seat
tube angle will affect the top tube length when comparing frames?
 
B

B.C. Cletta

Guest
> You say you want more information? No problem: I am 6'1, 33.6" inseam. The bike I currently have
> for road/light off road use(the first non mountain or BMX bike I have owned) is a Kona cyclocross
> bike, 58 cm center to top of seat tube, 57 cm top tube and a 10 cm stem. It shows about 6.5" of
> post to the bottom of the seat. It has a 31.2 cm bb height & 33.1" standover. I think it fits
> pretty well, but could be better.

how? (i don't care but you need to be able to answer it first and then do something about it.)
 
D

Death

Guest
Thanks for the response.

> Wow! Those are big differences. I'd be very concerned about the steep seat tube angle. What is the
> actual angle? That will certainly affect your
saddle
> position. You will have to move your saddle further back which will make your effective top tube
> length greater. Based on that alone, the smaller frame would appear to be the better choice. But I
> think I'd keep looking
for
> another brand that's more attuned to your ideal measurements.

The Soma frames have a 75.3 degree seat tube angle on their 57 frames, a 75 degree angle on their
59. The measurement of "ideal" frame is 73.5 degrees. How do you determine how much length the
sharper angle adds to the top tube/stem measurement? Also, the ideal frame has a 73.5 degree head
tube angle. The Soma frames have a 74.3 degree head angle on the 57 and a 75 degree head angle on
the 59. If the seat tube angle adds length in the comparison would the sharper head angle not
subtract length in the same way?
 
T

Tim McNamara

Guest
"death" <[email protected]*.no*spam> writes:

> The Soma frames have a 75.3 degree seat tube angle on their 57 frames, a 75 degree angle on their
> 59. The measurement of "ideal" frame is 73.5 degrees. How do you determine how much length the
> sharper angle adds to the top tube/stem measurement? Also, the ideal frame has a 73.5 degree head
> tube angle. The Soma frames have a 74.3 degree head angle on the 57 and a 75 degree head angle on
> the 59. If the seat tube angle adds length in the comparison would the sharper head angle not
> subtract length in the same way?

Basically, this is going to put you about 1.5 cm or so ahead of your "ideal" fit. Track bikes tend
to have steep head and seat tube angles and shallow offset forks (with a 75 degree head tube, you'll
want a fork with about 35 mm of offset, sometimes called rake. Not so easy to find, I hope the frame
comes with a fork). I like riding track bikes, my favorite commuting bike as a 20+ year old track
bike with a coaster brake hub.

I'm curious- why are you buying this frame rather than one that fits?
 
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